Powertrain, generic (extended)

P214F Reductant Heater A Current Too High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P214F concerns heater A of the DEF system, which Ford and GM both assign to the heater inside the tank (heater circuit 1). The code says this element consumed more current or power than intended. Ford's 2023 diesel summary performs one check per heating cycle, right after a cold start, and decides within 2.2 s when tank heater power is higher than expected. GM's 2025 Duramax tables set P214F when heater 1 current passes 15 A in 40 consecutive 100 ms samples; that is Type A and lights the MIL after one trip; the 2015 tables detected a shorted tank heater through a conductance of at least 0.62 S, Type B. A shorted element, wet connector or chafed lead is the usual reason. Without tank heating, frozen DEF thaws late or not at all, so dosing and NOx reduction start late in winter. P21DD is the low-current counterpart.

Likely causes

Tank heater element internally shorted (often replaced with the tank sender unit)
Water ingress or corrosion in the heater connector
Chafed heater wiring shorted to ground
Faulty heater driver in the reductant control module

Symptoms

  • Check engine light on
  • DEF system warning in cold weather
  • Delayed DEF dosing after cold starts

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–1,800
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

reductant tank heaterwiring harness

Related codes

P21DDP20B9P20BAP20BBP20BCP221D

References: fordservicecontent.com, gsi.ext.gm.com, gsi.ext.gm.com.